1. Technical Field
This invention relates to a pen tip structure which includes a rotatable ball socketed between the lip of the pipe and the end of an inner core.
2. The Prior Art
Ball point pens in which the ball at the pen tip part is rotated by frictional resistance during its writing movement so as to draw ink for writing are in, wide use throughout the world. One such known ball point pen utilizes a pen tip structure composed of a ball bearing shaft, a ball holding part within the ball bearing shaft, and a rotatable ball socketed between a bottom surface of the ball holding part and the tip of the ball bearing shaft, the bottom surface of the ball holding part being conically shaped and having an ink passage at its apex. Another known pen tip structure is constructed as shown in FIG. 47, wherein a ball receiving core (51) having a flat bottom surface is fixed in a ball holding pipe (50), with an axial ink passage space (52) being formed therebetween, and a ball (54) is rotatably held in a ball wrapping part (53) which communicates with the ink passage space (52). However, a pen tip structure which utilizes a ball holding part having a conical bottom surface has the following disadvantages: